Please forgive me for having to ask these questions, but I cannot say that I know the exact answers to either:
1. Why would the flaps and slats be down in the 15-degree position before the plane leaves the gate? (And then later, I was in seat 2B and saw a couple of "wheels" rolling at the same time the flaps were retracted approx. five minutes prior to pushback). What were these spinning wheels? This was a 737-300, by the way.
2. How fast is the average commercial airliner going when it touches down?
Any information is greatly appreciated as always.